Position determining apparatus and control method of robot

• US 5,804,942 A
• Filed: 07/22/1996
• Issued: 09/08/1998
• Est. Priority Date: 08/08/1995
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jeong, Joon-Young
• Primary Examiner(s): Sircus, Brian
• Application Number:
  US08/684,791
• Time in Patent Office: 778 Days
• Field of Search: 318/580-587, 364/423.098, 364/423.099, 364/424.027-424.033, 364/460, 364/461, 701/23-28
• US Class Current: 318/580
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00

Abstract

A self-propelled steerable robot emits ultrasonic waves in forward, rightward and leftward directions. On the basis of detecting those waves after being reflected from the walls, a controller on the robot determines an angle of travel of the robot relative to a wall of a room, enabling the robot to be turned and oriented parallel to opposite walls of the room. By then emitting waves toward those opposite walls and detecting the waves reflected therefrom, respective distances of the robot to those opposite walls can be determined. By turning the robot toward the longer of the two distances, and repeating the above steps, the robot can eventually become disposed at a center of the room. Then the robot advances from the center until reaching one of four known points in the room where the respective distances between both opposite walls changes. This enables the controller to determine where in the room the robot is located. The robot then travels along a predetermined path from that point.

Claims

1. A method of controlling a self-propelled, steerable robot having a control mechanism, comprising the steps of:

A) calculating an angle formed by the robot with a wall of a room to determine an extent by which the robot must be turned to become oriented parallel to two opposite walls of the room;

B) turning the robot by that extent to orient the robot parallel to the two opposite walls of the room;

C) determining two respective distances from the robot to the two opposite walls;

D) turning the robot in the direction of the larger of the two distances;

E) repeating steps C and D until the robot reaches a center point of the room;

F) advancing the robot from the center point parallel to two opposite walls of the room until reaching a predetermined point in the room where the respective distances from the robot to those two opposite walls change;

G) determining a present position of the robot in the room on the basis of the changed distances; and

then

H) advancing the robot along a predetermined path of travel from such present position.

2. The method according to claim 1 wherein step A includes swinging an ultrasonic wave emitter on the robot through a range of travel while emitting ultrasonic waves and sensing those waves once reflected from a wall toward which the robot faces, to determine a shortest distance to the wall, and calculating the angle on the basis of that shortest distance.

3. The method according to claim 1 wherein step C comprises emitting ultrasonic waves toward the two opposite walls and sensing the ultrasonic waves reflected from those two walls.

4. A self-propelled, steerable robot adapted to reach a center point in a room, comprising:

a controller;

obstacle detecting means for detecting an obstacle in front of the robot and for detecting respective distances from the robot to a pair of opposite walls of a room, the obstacle detecting means connected to the controller for transmitting signals therebetween;

turning means for turning the robot to the right or left, and connected to the controller for transmitting signals therebetween;

turning angle detecting means for detecting an angle of turning when the robot turns to the right or left sufficiently to face the one of the pair of walls located farthest from the robot, the turning angle detecting means being connected to the controller for transmitting signals therebetween; and

propelling means for propelling the robot toward the one wall;

the controller including travel distance detecting means connected to the propelling means for detecting a travel distance of the robot and determining when the robot travels to a point midway between the pair of walls.